2+δ‐Dimensional Materials via Atomistic Z‐Welding

Abstract Pivotal to functional van der Waals stacked flexible electronic/excitonic/spintronic/thermoelectric chips is the synergy amongst constituent layers. However; the current techniques viz. sequential chemical vapor deposition, micromechanical/wet‐chemical transfer are mostly limited due to diffused interfaces, and metallic remnants/bubbles at the interface. Inter‐layer‐coupled 2+δ‐dimensional materials, as a new class of materials can be significantly suitable for out‐of‐plane carrier transport and hence prompt response in prospective devices. Here, the discovery of the use of exotic electric field ≈106 V cm− 1 (at microwave hot‐spot) and 2 thermomechanical conditions i.e. pressure ≈1 MPa, T ≈ 200 °C (during solvothermal reaction) to realize 2+δ‐dimensional materials is reported. It is found that Pz—Pz chemical bonds form between the component layers, e.g., C—B and C—N in G‐BN, Mo—N and Mo—B in MoS2‐BN hybrid systems as revealed by X‐ray photoelectron spectroscopy. New vibrational peaks in Raman spectra (B—C ≈1320 cm–1 for the G‐BN system and Mo—B ≈365 cm–1 for the MoS2‐BN system) are recorded. Tunable mid‐gap formation, along with diodic behavior (knee voltage ≈0.7 V, breakdown voltage ≈1.8 V) in the reduced graphene oxide‐reduced BN oxide (RGO‐RBNO) hybrid system is also observed. Band‐gap tuning in MoS2‐BN system is observed. Simulations reveal stacking‐dependent interfacial charge/potential drops, hinting at the feasibility of next‐generation functional devices/sensors.


Section1: XRD details of RGO-RBNO, MoS 2 -WS 2, and MoS 2 -RBNO system
A hybridized sample of RGO-RBNO was studied using the X-ray diffraction technique (XRD) to have a glimpse of inter-layer coupling and find out new hybridized peaks due to C-B and C-N bond formation. When XRD measurement was performed on the GBNH sample, we observed 2θº peaks at 26.5º, 41.4º, 43.6º, 54.9º, 59.4º, 71.2º, and 75.8º. Similarly, GBNS exhibited XRD peaks at 26.7º, 41.4º, 43.9º, 56.1º, 59.5º, 71.3º, and 75.9º. When microwave power was used as an exotic condition (temperature and electric field) for hybridizing and obtained product was diagnosed with XRD measurement, it exhibited peaks at 26.60º, 41.4º, 43.7º, and 55.0º, respectively 59.7º, 71.3º, and 75.7º. XRD peak at~ 26.0º of B.N. corresponds to {002} facet of hexagonal closed pack structure shifted from their original position 0.5º for GBNH, 0.7º for GBNS, and 0.6º for GBNM sample. We observed a change in inter-layer dspacing from ~3.42 Å to 3.3 Å for the GBNM sample, which was ~2.1 % less than their original d-spacing. XRD is a bulk characterization technique that gives information at a macro level; any minute changes in the micro-level will not be detected by XRD. However, the Shift in micron level is moderately significant; we expect more changes would have occurred at the local atomic level, and M.D. simulation results support the same; the local distance waschangedfrom3.3Åto2.7Åatthe MoS 2 and WS 2 being semiconductors, with bandgap (1.4 to 1.9 eV), both exhibit direct band gaps only when synthesized in monolayer. Synthesizing the monolayer of MoS 2 and WS 2 using scotch tape and sonication is a cumbersome process, whereas CVD is expensive and non-scalable. Overcoming such hurdles, we combine these two-dimensional materials to tune their excitonic behaviors by hybridizations (heating, solvothermal, and microwave). XRD measurement was performed for hybridized ( 14.1º in the microwavehybridized sample is also distinct peaks were observed in X-ray diffraction at 29.0º, 44.0º, and 60.1º due to hybridization between MoS 2 and WS 2 . Inter-layer d-spacing was reduced to 6.2 Å in contrast to 6.3 Å for pure WS 2 slight reduction in inter-layer d-spacing was observed because of the global stacking effect. Still, at the local level, it is expected to reduce even higher.

Section 2 Raman and FTIR measurement
The 2D atomic layer constitutes atoms bound with strong covalent bonds (in-plane), whereas the out-of-plane direction exhibits van der Waals's nature. When hybridized between RBNO, RGO, MoS 2, and WS 2 is exhibited various bond formations. These bonds can be catalyzed by external perturbation by optical and electrical energy and will suffice for atomic rotational and vibrational transitions. Thus, various characteristics of vibration bond energy will be observed when diagnosed with Raman and Fourier transfer infrared (FTIR) spectroscopies. the 760cm -1 representsanout-of-plane bending mode of B-N-B, and 1320 cm -1 is due to the B-N stretching mode. After hybridization, a new vibration mode at 1727.6 cm -1 (C-N) was observed. Similarly, a bond at (~ 1212-1270) cm -1 was found due to C=N vibration 13-14, 16-17 . A bond at 2928 cm -1 was due to symmetric stretching mode, and 2973 to 2985 cm -1 was due to asymmetric stretching mode of CH 3 after reducing functional group COOH to CH 3 15 . cm -1 (D+D′), 2586 cm -1 (2D band) and 2702 cm -1 . Similarly, for the GBNM sample, in addition to pressure and temperature, a high electric field (~ 10 6 V/cm) led to the strong interlayer coupling between (RGO-RBNO) system when it was diagnosed with Raman measurement. We observed different peaks at 1319 cm -1 due to (C-N) 11 bond formation 1350 cm -1 (B-N vibration), 1579 cm -1 (G band), 1603 cm -1 (D′), 2994 cm -1 (D+D′), and 2547 cm -1 ((2D band) 10,12 . Hybrid materials are supposed to exhibit new vibration modes and splitting of Raman modes of an individual layer. The same has been observed after the deconvolution of 2D peaks. A similar effect was observed in D peak intensity, which increased due to hybridization. The effect electric field was observed during Raman measurement by varying the electric field value from 0 V to 13 V in the RGO-RBNO system. When the voltage value was zero, Raman peaks were observed at 1296 cm -1 , 1351 cm -1 (B-N) vibration, 1586.7 cm -1 (G band), and 1614.9 cm -1 (D′) band. Similarly, when the voltage was changed to 5 V, it exhibited Raman peaks at 1314 cm -1 (C-N) 11 vibration mode, 1365 cm -1 (B-N) vibration, increased to 12 V, it displayed Raman modes at 1294.06 cm -1 , 1340.49 cm -1 (B-C) 8 vibration modes from B 4 C like-structure, 1368 cm -1 (B-N) vibration mode, 1394.5 cm -1 , 1578.8 cm -1 (G band), and 1616.9 cm -1 (D′) band. When voltage was further increased to 13 V, it exhibited Raman modes at 1290 cm -1 , 1319 cm -1 (C-N) 11 vibration, 1364.7 cm -1 (B-N) vibration, 1576.3 cm -1 (G band), and 1615 cm -1 is due to (D′) band. Inter-layer coupling and bond formation in the hybridized (RGO-RBNO) sample, influenced by an electric field and these vibration modes, were activated when we increased the voltage 12-13 . When Raman measurement was performed under an applied electric field, the G band (C-C bond stretching mode) in RGO due to sp 2 carbon atoms was red-shifted as we increased the voltage from 0 V to 13V. Such red sifts in the G band signified electric field-induced doping in RGO-RBNO. Also, it suggests a strong modification of DOS with new states formation along with bandgap opening in the E-K energy band diagram. Also, linear E-K behavior changed parabolic nature at Γ point upon field doping. (h) ∆ ω between E 2g and A 1g modes due to hybridization. The minimum was observed for the MBNMI sample. (i) Raman spectra for MoS 2 and WS 2 hybridized (MWH, MWS, and MWM) samples (j) A 1g vibrational position of MoS 2 (k) ∆ ω difference between E 2g and A 1g modes for MoS 2 due to hybridization. (l) Intensity ratio for A 1g /E 2g peaks for MoS 2 samples when hybridized with WS 2 .
Similarly, RBNO was hybridized with MoS 2 with an adequate supply of energies (temperature, pressure, and electric field energy). These layers (RBNO and MoS2) are expected to come close to each other as an effect of Mo-N, Mo-B, and N-S bond formation is desired. FTIR peaks at 758 cm -1 due to B-N-B out-of-plane bending mode and 946, 1327cm -1 due to B-N stretching mode. The out-of-plane vibration mode of B-N blue-shifted 10 cm -1 in BNMM hybridized sample, primarily due to interaction with neighboring MoS 2 sheets; and possibly out-of-plane bond formation. Their elastic behavior will change depending upon bonding nature (strong or weak); consequently, effective frequencies will shift from their original positions. Similar behavior was exhibited by the BNMS sample, where the B-N stretching mode got shifted by 8 cm -1 . Active sites available during the hybridization (B and N) are more likely to interact with MoS 2 ; due to the offset of S atoms from MoS 2 atomic sheets, the stretching vibration frequency of B-N will change. When Raman measurement was performed on BNMH, it exhibited Raman peaks at 365 cm -1 due to hybridized (Mo-B) bond, 370 cm -1 (E 2g mode), 400 cm -1 (A 1g mode), and 449 cm -1 (2LA mode) modes of MoS 2 and 1357 cm -1 are due to B-N. It is noteworthy that a systematic blue Shift was observed in B-N (1350 cm -1 ) vibrational mode in Raman measurements. The shifts were 3.7 cm -1 for BNMH, 6.2 cm -1 for BNMS, and 7.1 cm -1 for BNMM samples.
Similarly, difference ∆ω (E 2g -A 1g ) modes of MoS 2 due to hybridization were found at 30.2 cm -1 for BNMH, 26.8 cm -1 for BNMS, and 28.2 cm -1 for BNMM samples. Decreased ∆ω manifest hybridization and various bond formations (Mo-B and Mo-N). Also, we have found that phase transformation of MoS2 (2H to 1T) is more prominent in solvothermally hybridized samples compared to heat-mediated and microwave-based hybridized samples. We have also performed new Raman measurement in our hybrid samples and found that more prominent 1T phase Raman vibration modes [36][37] at ~219 cm -1 and ~315 cm -1 for Solvothermally hybridized sample (BNMS) in contrast to heat mediated (BNMH) and microwave hybridized (BNMM) samples.
When MoS 2 is hybridized with WS 2, upon hybridization, from MoS 2, Mo and S atom will interact with WS 2 (both active sites W and S) and vice versa; as an effect, Mo 1-x W x S 2 like-new crystal structure formation is expected. Raman vibration mode E 2g (in-plane vibration) of constituent atoms, whereas A1g (out-of-plane) shift of S atom from existing (MoS 2 and WS 2 ) atomic sheets are sensitive to measurements. When Raman measurement was performed in hybridized MWH (heating) sample, it exhibited a peak at 288, 319, 344, 373, 400, 415, 444, 516, 576, and 625 cm -1 . Likewise, MWS (Solvothermal) sample exhibited Raman modes at 293, 338, 346, 375, 400, 416, 446, 577, 519 and 633 cm -1 . Similarly, MoS 2 was hybridized with WS 2 by microwave (MWM), and the response will differ due to their different dielectric constants in the GHz frequency range. Also, a high electric field (~10 6 V/cm) and localized heating (~ 2000 ºC). Although hybridization was performed in the liquid medium, it will push atomic sheets (MoS 2 and WS 2 ) even closer to each other. As an outcome, the inter-layer coupling will enhance. When Raman measurement was performed it revealed various vibration modes at 286, 322, 345, 373.5,400,414,444,516,577and622cm -1 . Generally, exfoliated MoS 2 sheets exhibits Raman modes at370cm -1 ( E 2g ), 400cm -1 (A 1g ), 452cm -1 ( 2LA), 517cm -1 ( E 2g +2LA), 577cm -1 ( E′ 2g +LA) and 622 cm -1 (A 1g +LA). Similarly, exfoliated WS 2 sheets exhibit Raman modes at 175 cm -1 ( LA),265cm -1 ( 2LA-3E 2G ),230cm -1 ( A 1g -LA),296cm -1 ( 2LA-2E 2g ),352cm -1 ( 2LA),355(E′ 2g ), 418 cm -1 (A 1g ), 581 cm -1 (A 1g +LA) and 702 cm -1 (4LA). In general, Raman E 2g (in-plane vibration) and A 1g (out-of-plane vibration) modes are considered the most important Raman signature in exfoliated MoS 2 and WS 2 sheets and therefore were diagnosed minutely in hybridized sheets, and their effect on hybridization was studied 4,18-23 . The difference (E 2g -A 1g ) in Raman modes, i.e., ∆ω for MoS 2, was 27.24 cm -1 for MWH and 25.8 cm -1 for MWS hybridized sample. Likewise, forWS 2 difference(E 2g -A 1g ) ∆ωwasfoundtobe70.54 cm -1 for MWHand68.9 cm -1 for the MWM sample. Such a significant Shift hint at the hybridization and bond formation between the MoS 2 and WS 2 system; as an effect, its intensity ratio (A 1g /E 2g ) was changed.   Like the RGO-RBNO hybrid system, it is very intriguing to check hybridization and its corresponding change in the atomic arrangements of hybrid RBNO-MoS 2 systems. Therefore, we hybridized RBNO with MoS 2 by Heating, solvothermal, and microwave (see camera image in Fig. (S9)). When the BNMH sample was diagnosed with TEM (see Fig. S10 (a)), we observed a highly transparent sheet corresponding to the MoS 2 sheet covered with oval-shaped 2D sheets of B.N. sheets. The overlapped area was estimated at ~ 200 nm, which was further validated by elemental mapping, which gave clear proof, i.e., the presence of both MoS 2 and RBNO sheets. When the overlapped area was minutely diagnosed with HRTEM moirés pattern was observed, which signifies the hybridization between MoS 2 and RBNO (due to inter-layer coupling). When FFT was acquired in the overlapped area of HRTEM, it exhibited mixed-fold symmetry (6-fold with 2-fold) (see inset Fig. S10 (b)). Such variation in symmetry suggests the influence of foreign atomic sheets (MoS 2 ) over RBNO sheets. The average nuclear distance was measured in the HRTEM image across the atomic line and found to be ~2.5 Å, whereas, along the atomic line, it was ~2.1 Å. Signify the highly strained system due to strong interlayer coupling. In contrast, the equilibrium distance for B.N. is~1.54Å, and for MoS 2, it is~3.1 Å. Similarly, the BNMS sample was examined by TEM imaging highly transparent, and folded MoS 2 sheets were observed. This is characteristic of monolayer MoS 2 along with oval-shaped B.N. sheets. The overlap area was estimated to be ~150 nm, confirmed by elemental mapping. When the overlaying area was examined by HRTEM, we could resolve the individual atoms; the atomic arrangements also suggested a moirés pattern, possibly due to overlapping between distinct atomic sheets with some rotational angle. FFT pattern in an overlap area exhibited sixfold symmetry, possibly due to A.A. stacking. Measuring the atomic distance in the obtained moirés pattern will be interesting, as it will have different distances than their parent atomic sheets; hence we measured average atomic distances. Along the atomic line, itwas~3.45Å; across the atomic line, it was 3.0Å. It signified that MoS 2 atomic distance had It has been reduced ~ 3 % significantly from its equilibrium distance of 3.15 Å; due to the presence of B.N. sheets in the vicinity of MoS 2 sheets. Moreover, the MBNMI hybrid sample was hybridized in the liquid medium, where the localized temperature was moderately high with an extremely high electric field. Such dynamic conditions excelled RBNO and MoS 2 sheets close enough where bond formation occurred. When the hybridized sample was examined by TEM measurement, it exhibited transparent sheets with sharp-edged MoS 2 sheets and oval-shaped B.N. sheets extending up to more than 200 nm in lateral dimension, with an overlap area of ~100 nm. The presenceofMoS 2 andRBNOintheoverlapareawasfurtherconfirmedbyelementalmapping.
The overlap area was revisited by HRTEM measurement; atoms were linearly arranged in some places (plausibly moirés pattern), whereas it exhibited hexagonal patterns in some places. When the FFT pattern was observed, it showed 6-fold symmetry. Localized change in interatomic distance will be exciting because it will alter its electronic and optical properties. Therefore, we carried out atomic distance measurements obtained from the HRTEM image. Along the atomic line, it was ~3.2 Å, and across the atomic arrangement, it exhibited ~3.0 Å. MoS 2 and WS 2 are of great interest due to their potential applications in optoelectronics, photocatalysis, sensors, and photovoltaics. Hybridizing such 2D materials will unveil various applications starting from energy storage, excitonics, transistors, and many more. Conventional hybridization techniques, e.g., CVD grow sheets, wet chemical transfer, and scotch tape transfer methods, have some limitations for device applications. The diffused interfaces during growth, residual contamination (water molecules and glue), and scalability are major concerns. We have tried to address the existing problem by exfoliating a few layers of MoS 2 and WS 2 in large quantities and hybridizing by heating, solvothermal, and microwave (see camera image of hybridized sample Fig. S12). The resulting hybridized sample was diagnosed by TEM imaging to know the effect of hybridization at the atomic scale. When the hybridized MWH sample was Analyzed with TEM, observed highly transparent sheets with lateral dimensions of more than ~150 nm correspond to MoS 2 sheets, covering WS 2 sheets of ~30 nm (see Fig. S13 (a)). The presence of both atomic sheets in the overlap area was confirmed by elemental mapping (see Fig.S12 (d)). When overlapping areas 1& 2 were minutely diagnosed with HRTEM imaging, we noticed a hexagonal pattern in a few places along with a moirés pattern (characteristic of inter-layer coupling) that suggests interaction leading to bond formation amongst atomic sheets. The hybridized area was further studied by measuring the interatomic distance and found across the atomic line ~3.15Å and along the atomic line ~3.0 Å. Similarly, MWS hybridized sample was diagnosed by TEM imaging; we observed highly transparent folded WS 2 sheets of ~ 200 nm wrapping the MoS 2 sheet, which were tiny sheets of ~ 50 nm(See Fig.S13 (b)). Elemental mapping confirmed the coexistence of MoS 2 and WS 2 sheets. When the overlying areas 1&2 were minutely examined by HRTEM measurement, they exhibited the atomic arrangement in a hexagonal manner. The FFT pattern further validated this; it showed (6-fold symmetry). Atomic distances obtained from HRTEM along the atomic line were ~3.15Å, whereas, across the atomic line, it was ~3.0Å. When MWM hybridized sample was examined by TEM measurement, multilayer highly transparent sheets were observed lengthened up to ~250 nm, covering the WS 2 atomic sheets ~30 nm (see Fig.S13 (c)). Elemental mapping revealed the presence of both MoS 2 and WS 2 sheets. When such overlapped areas 1&2 were diagnosed with HRTEM, it exhibited a moirés pattern over the entire area; it signifies the strong inter-layer coupling as an effect of high electric field and supercritical heating under liquid medium. FFT pattern was performed over the underlying area; it exhibited six-fold symmetry, which suggests possible A.A. stacking. Inter-atomic distances were measured over the moirés pattern vertically and horizontally from the HRTEM image; it turned out that the vertical distance was ~3.15 Å and was larger than the horizontal distance of ~ 3.0Å.

Section 4: XPS details of RGO-RBNO RBNO-MOS 2 and MoS 2 -WS 2 hybridized sample
Effect of hybridization on hybridized samples (GBNH, GBNH, and GBNM) attained by various processing conditions (heating, solvothermal, and microwave) and their effect on interlayer distance and the interlayer coupling in-depth. Due to dynamic processing conditions is very important to diagnose with XPS for better understanding. XPS measurements were performed on hybridized GBNH sample (Survey shown in Fig.S15 (a)) and a short-range scan for B1s, C1s, and N1s spectra (see Fig.S15(b)-(c)). Upon deconvolution of B1s, spectra's stretches at189.6eV(B-C), and 190.9 eV (B-N) bonds were obtained. Similarly, after deconvolution of C1s spectrum, we observed stretches at 282.8eV(B-C) B 4 C likestructure,283.4eV(B-C) BC 3 like-structure, 284.2 eV(C-C) bond, 285.5 eV(C-N) bond, and 288.0 eV corresponding to C-O bond. Likewise, the N1s spectrum after deconvolution exhibited stretches at 397.1eVcorresponding to the B-N bond,98.4 eV C-N pyridinic like a bond, and 399.3 eV (C=N) pyrrolic like a bond. Inter-layer coupling was expected to get even stronger when additional dynamic condition pressure was involved in hybridization. Therefore, we carried out an XPS measurement of the GBNS sample (survey shown in Fig.S15 (d)) and a short-range scan for B1s, C1s, and N1s spectra (See Fig. S15 (e)-(f)). Upon deconvolution of B1s spectra, stretches at 189.7 eV (B-C) due to BC 3 like-structure and 190.6 eV due to sp 2 bonded (B-N) were obtained. Likewise, after deconvolution of the C1s spectrum, we observed stretches at 283.5 eV (B-C) BC 3 like-structure, 284.4 eV due to sp 2 hybridized C-C bond, 285.1eV is because of C-N and 286.60 eV Corresponding to C-O bond. Similarly, the N1s spectrum after deconvolution exhibited stretches at 397.2 eV corresponding to the B-N bond, 398.0 eV C-N due to the pyridinic bond, and 405.5 eV because of the N-O bond. When microwave was employed for hybridization, dielectric heating due to oscillating electric field and high electric field will catalyze the reaction, and inter-layer distance will be further reduce. When XPS measurement was performed on GBNM hybrid sample (see survey in Fig. S15 (g)), and short-range scans for B1s, C1s, and N1s spectra (see Fig. S15 (h-i)). Upon deconvolution of B1s spectra, stretches at 189.7 eV (B-C) bond and 190.7 eV (B-N). Likewise, the N1s        DFT band structure calculation for BN-MoS 2 hybrid when the inter-layer distance was reduced from 3.3 Å to 2.7 Å, exhibited band gap was increased from 2.7 eV to 2.9 eV.

Section 5: Bond formation energies of various bonds and suitability of the techniques
In our hybridization techniques, such as the solvothermal technique, pressure is the main candidate that decides the chemical bond formation between the different atomic sheets. The pressure built up inside the solvothermal reactor depends upon the choice of solvents and temperature of the reactor. In our case, we've chosen DMF due to its reducing nature, and the reactor temperature was ~200℃. Using the above equation for T =200℃ to the obtained vapor pressure of DMF within the reactor by substituting the constant values in the equation we obtained a pressure is ~0.5 MPa. These conditions (pressure ~0.5 MPa and temperature~200 ℃) are sufficient for bond formation. As it was discovered in the case of graphite sp 2, that gets converted to graphite-like Dimond (sp 2 +sp 3 ) at elevated temperature and pressure. The P-T diagram for such conversion is shown in Fig.S24  Similarly, the microwave-based processing method for hybridizing different atomic sheets depend upon microwave power. The microwave power absorption relies upon the material's dielectric and magnetic properties (if the sample is magnetic in nature). The power absorbed by the material inside the microwave reactor in liquid medium is given by Where P is power f is the frequency of the microwave, E is the electric field because of microwave, ϵ 0 = 8.8X10-14, ε'represent the relative dielectric constant due to material and solvent, μ 0 =4π × 10−7 H/m, μ' represent relative permeability of the material and H is the magnetic field. Our materials are intrinsically nonmagnetic in nature; therefore, the second term isn't significant. So, the power absorbed by the material is given by = ( ′ ) … … … … … … … … … … … … … … … … … ( ) GBNM hybrid material dielectric constant is ε'=6.8 at 2.45 GHz obtained from experimental measurement as shown in Fig.S25 for GBNS, GBNH, and GBNM samples. The distribution of the electric field inside the microwave oven was obtained from the simulated result. As shown in Fig. S26 [28] Fig. S26 Electric field distribution for the sample with ε ′ = 6.25 and frequency of 2.45 GHz [28] .
Using dielectric constant ~ 6.8 obtained from experimental dielectric measurement for GBNM hybrid and electric field value ~2 x10 2 to 4x10 4 V/m [29][30] obtained from numerous simulation results, in equation (3) and calculated absorbed power for our materials, it turns out to be ~ 0.38 eV/atom. When the microwave is brisked in a pulsed manner of ~ 60 s, the global temperature inside the reactor where DMF is present can go up to ~200 ℃ within a very short duration of time, ~ 60s [31] , which will cause additional pressure ~0.5MPa inside the microwave reactor. The energy because of pressure built up inside the reactor is ~ 0.41 eV. Hence the adequate energy received by atoms within the microwave oven is ~ 0.41+0.38= 0.79 eV/ atom. The skin depth is obtained by using the subsequent formula [32] = . √ ′ ( ′′ ′ )

………………………. (4)
Here ω is the frequency of the microwave, ε'=6.8 is the real part, and ε''=2.55 is the imaginary part of the dielectric constant at 2.45GHz in the case of the GBNM sample. Substituting all values in equation (4) to obtain penetration depth, it turns out to be ~ d=11.47 mm. Thus, our material exhibited low loss, which is suitable for better microwave absorption and minimal conversion of microwave energy into heat energy.